Vibration generator

ABSTRACT

The invention relates to the field of transducers, in particular linear vibration generators. It concerns a vibration generator, devices comprising such a vibration generator and a related treatment method. 
     A vibration generator comprising a mass, a coil, a permanent magnet and a housing, wherein the mass can be set in an oscillatory motion with respect to the housing by applying a current to the coil, and the vibration generator further comprising an axle, wherein the oscillatory motion is along the axle, and in that the mass comprises the permanent magnet and the coil is fixed to the housing.

FIELD

The invention relates to the field of transducers. It concerns avibration generator, in particular a linear vibration generator. Thevibration generator is in particular—but not exclusively—suitable fordevices for medical applications, in particular medical devices forstimulation of a subject by oscillations (vibrations), in particularvibration therapy such as modulated vibration therapy. Sound-vibrationaltherapy, therapy by acoustic energy, therapy by ultrasound or therapy byinfrasound are examples of (modulated as the case may be) vibrationtherapies. The invention relates further to a device for oscillation(vibration) therapy comprising the vibration generator and to a relatedmethod.

BACKGROUND

Linear vibration generators comprise a mass that can be actuated tocarry out an oscillatory motion along an axis. Therefore, the vibrationgenerator comprises a permanent magnet or an electromagnet, a coil, andmeans for generating a repelling force.

There are various kinds of linear vibration generators known. Inconsumer electronics, a linear vibration generator usually comprises apermanent magnet or an electromagnet that is firmly mounted to a hosingof the vibration generator and a coil that is firmly mounted to themass.

State-of-the-art linear vibration generators are rather complex in termsof number of parts and design. US 2019/0068039 A1 and WO 2011/043536 A1show example of state-of-the-art vibration generator. Often, they workat resonance frequencies of the oscillatory motion in order to beefficient and to have a high response sensitivity and/or they areoptimized for a narrow frequency range. WO 00/058505 A1 discloses avibrator optimized for the very low frequency range, this means for thefrequency range below 30 Hz.

Devices for oscillation (vibration) therapy are well-known in theexemplary field of medical applications.

For example, WO 2011/159317 A1 discloses a pain abatement device thatprovides for multiple sensory inputs, wherein the multiple sensoryinputs are generated by temperature, a tactile input and vibration byutilizing multiple small vibratory motors.

US 2012/0253236 A1 discloses wearable devices for externally deliveringtherapeutic stimulation to improve health, condition and performance.The stimulation is done via vibration, tones, audio or electrical pulse,light or other sources. In embodiments, the device comprises a regularor vibration speaker or a vibrating component with a motor.

US 2003/0172939 A1 discloses a method and a device to relieve discomfortby attaching a vibration generating means to hard tissue of thepatient's head and by applying vibrations at a subsonic frequency.

US 2008/0200848 A1 discloses a method and a device for treating nasalcongestion and/or relieving sinusitis symptoms, in particular bycombining vibrational stimulation and a stream of fluid forced towardsthe patient's respiration tracks.

US 2013/0253387 A1 discloses systems and methods for treating anoccluded area in a body or for reducing pathologic material in the body,for example. Therefore, vibratory energy is applied to pathologicmaterial in a treatment area of the body. The vibratory energy isprovided to the treatment area by use of a piezoelectric transducer andan effector, wherein the effector can be designed to reach into theoccluded area or to be positioned on a forehead or another external bodyportion.

WO 2010/113046 A1 discloses a device for the ventilation of nitric oxidein the paranasal sinuses and to suppress disorders of the upperrespiratory tract. The device comprises a vibration generator, avibration transmitter in mechanical/physical contact with the vibrationgenerator, and a control unit. The vibration generator contains anelectric motor and an eccentric wheel. Control unit, vibration generatorand vibration transmitter are designed to allow for a fast revolutionchanges in a given frequency range.

CN 108704 826 A describes a device having an axle i.e. guiding column(2) comprising two ends which are covered by a first and second fixingmember (6, 10) upon which a first and second coil is wound (1, 4). Amagnet is placed in the middle of the axle (2).

WO 2015/030602 A1 describes a vibrator apparatus for stochasticvibrations. The vibrator apparatus (34) comprises a moving coil (35)which is rigidly attached to a member (1″), e.g. a frame or beam, of avibration device (1), the moving coil (35) for an elected vibration modeof the apparatus being configured to receiving electric signals, e.g.pulsating and/or sinusoidal electric signals from a signal unit (25),and the moving coil (35) co-operates with a permanent magnet (48) whichis suspended by springs (49, 50; 93, 94) attached said member (1″), andthe coil (35) and the magnet (48) are mutually linearly and coaxiallymovable upon application of said electric signals to the moving coil(35). The stated purpose of the apparatus is to provide externalstochastic noise having allegedly positive effects on for examplehearing, ADHD and dopamine-related neurodegenerative disturbances, suchas akinesia, Parkinson and aging.

U.S. Pat. No. 3,366,749 A describes an audio transducer having an axlei.e. moving post 6 having a rod 10, a voice coil 16 and a permanentmagnet 8 both of which surround the axle. Resilient mounting means 9appears to hold the magnetic assembly and is attached to the axle.

DE 10 2015 209639 A1 is related to mobile phone technology and describesan electromagnetic linear actuator creating a haptic output. Theactuator has an axle i.e. shaft 320, a moving mass/central magnet array310 and a coil 300.

JP 2005 348815 A describes a vibrating massage apparatus for the humanbody for fatigue recovery and blood circulation improvements. Theapparatus has a mass that extends from a spring member but an axle doesnot appear to be present.

State-of-the-art vibration generators are not suitable for manyapplications, in particular medical applications. Their design cannot beadjusted easily to different frequency ranges and/or their frequencytuning properties are limited and/or far from being linear. Further, theimpulse that can be generated is not sufficient for many applicationsfor example medical applications.

SUMMARY OF THE INVENTION

In a first aspect of the invention there is provided a vibrationgenerator comprising a mass, a coil, a permanent magnet and a housing,wherein the mass can be set in an oscillatory motion with respect to thehousing by applying a current to the coil, and the vibration generatorfurther comprising an axle, wherein the oscillatory motion is along theaxle, and in that the mass comprises the permanent magnet and the coilis fixed to the housing.

In embodiments the permanent magnet is a ring magnet, wherein the ringmagnet and the coil are arranged concentrically around the axle.

In a further embodiment the mass comprises a slit, wherein the slit isarranged concentrically with respect to the axle and wherein the coil isarranged in the slit.

In another embodiment the mass and the permanent magnet are configuredto generate an essentially homogeneous field in a section of the slit,wherein the homogeneous field runs radial to the axle in this section ofthe slit.

In embodiments the section is formed between a core ring and a corebottom, wherein the core ring is of a material having a high saturationlevel and wherein the core bottom is configured to not exceed asaturation limit of the material having the high saturation level.

In a further embodiment an extension of the coil in a direction parallelto the axle is smaller than an extension of the section in a directionparallel to the axle and wherein the vibration generator is configuredsuch that the coil is in the section independent of the orientation ofthe vibration generator.

In another embodiment the vibration generator is configured for theoscillatory motion being restricted between two positions of maximumdeflection of the mass and wherein the vibration generator is configuredfor the coil being predominantly in the section of the homogeneousfield.

In embodiments an extension of the coil in a direction parallel to theaxle is larger than an extension of the section in a direction parallelto the axle, wherein the vibration generator is configured for theoscillatory motion being restricted between two positions of maximumdeflection of the mass and wherein the vibration generator is configuredfor a portion of the coil extending over the full extension of thesection independent of the position of the mass.

In a further embodiment the vibration generator comprises an elasticelement that centers the mass when the vibration generator is notpowered.

In another embodiment the elastic element is compressed during operationof the vibration generator.

In embodiments the vibration generator is configured to have its basicharmonic outside the frequency range in which the vibration generator isoperated.

In a further embodiment the vibration generator is configured to have noharmonics of significance with respect to the amplitude of anoscillatory motion of the mass in the frequency range in which thevibration generator is operated.

In another embodiment the coil is mounted on a support having good heattransfer properties, wherein the support is in thermal connection to thehousing, and wherein the housing is of a material capable to absorb heatgenerated by the coil and transferred to the housing via the support.

In embodiments the vibration generator further comprises a signalprocessing unit, wherein the signal processing unit is configured tosuperimpose a control signal used for the oscillatory motion of the masswith a further signal, wherein the further signal and the vibrationgenerator are configured in a manner that an audible signal can begenerated from the further signal by the vibration generator.

In a further embodiment the vibration generator is configured to sweepover a plurality of frequencies.

In another embodiment the vibration generator is configured to oscillateat a frequency of not less than 1 Hz, 5 Hz, 10 Hz, 20 Hz, 30 Hz, 40 Hz,50 Hz, 60 Hz, 70 Hz, 80 Hz, 90 Hz, or 100 Hz.

In a further embodiment the vibration generator is configured tooscillate at a frequency of not more than about 2000 Hz, 1900 Hz, 1800Hz, 1700 Hz, 1600 Hz, 1500 Hz, 1400 Hz, or 1300 Hz.

In embodiments the vibration generator is configured for oscillations inthe range of 1 Hz to 2000 Hz, more suitably in the range of 20 Hz to1500 Hz, and optionally in the range of about 60 Hz to about 1300 Hz.

In a further embodiment the vibration generator is configured to sweepover a frequency range of about 60 to about 1300 Hz, or a sectionthereof.

In another embodiment the sweep occurs over a time period of at mostabout 60 s, 45 s, 30 s, 25 s, 20 s, 15 s, 10 s, or 5 s.

In a further aspect there is provided a device for applying oscillationsto a subject to be stimulated, comprising a vibration generatoraccording to the preceding aspect and embodiments.

In a further embodiment the device comprises a device head and a devicebody, wherein the vibration generator is arranged in the device head.

In another embodiment the device head is movable to a first positionrelative to the device body and to a second position relative to thedevice body, wherein the device comprises a controller configured toswitch the device in a sleeping mode if the device head is moved to thefirst position and to switch the device in an active mode, if the devicehead is moved to the second position.

In embodiments the device head is movable to a third position relativeto the device body, wherein the third position allows access to acontact surface for cleaning and wherein the controller is configured toswitch the device in the sleeping mode if the device head is moved tothe third position.

In another aspect there is provided a method for treating a subject withoscillations, characterized by comprising a step of bringing a devicecomprising a vibration generator according to one of the above aspectsand embodiments in contact with the subject.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 an exterior view of an exemplary embodiment of a devicecomprising a vibration generator;

FIG. 2 an external view of a further exemplary embodiment of a devicecomprising a vibration generator;

FIG. 3 an external view of yet a further exemplary embodiment of adevice comprising a vibration generator;

FIG. 4 an exploded view of device shown in FIG. 1;

FIG. 5 an exploded view of an exemplary embodiment of the device headshown in FIG. 1;

FIG. 6 an exploded view of a further exemplary embodiment of a devicehead;

FIG. 7 a sectional view of the device head of FIG. 5;

FIG. 8 an exploded view of an exemplary embodiment of a vibrationgenerator;

FIG. 9 a sectional view of the vibration generator of FIG. 8:

FIG. 10 a detail view of an actuation region of the vibration generatorshown in FIG. 8;

FIG. 11 a detail view of an alternative embodiment of the actuationregion; and

FIGS. 12-15 CRS treatment as an application example.

DETAILED DESCRIPTION

As used herein, the term ‘comprising’ means any of the recited elementsare necessarily included and other elements may optionally be includedas well. ‘Consisting essentially of’ means any recited elements arenecessarily included, elements that would materially affect the basicand novel characteristics of the listed elements are excluded, and otherelements may optionally be included. ‘Consisting of’ means that allelements other than those listed are excluded. Embodiments defined byeach of these terms are within the scope of this invention.

Embodiments of the vibration generator and the device according to theinvention are in particular suitable for vibration therapy, inparticular modulated vibration therapy, that is applied to an exteriorbody portion.

In embodiments suitable for modulated vibration therapy, the frequencyis modulated at least, for example by applying a sweep as disclosedbelow.

Vibration therapy is used for several medical applications such aschronic rhinosinusitis (CRS), migraine, chronic wound healing, painrelief, and muscular tension. There are indications of a potential useof vibration therapy in various further medical applications as pointedout below.

The main advantages of (exterior) vibration therapy over other therapymethods are its non-invasive, drug-free and safe character withoutsignificant loss of local applicability if directed vibrations (asprovided by the vibration generator according to the invention) areused. Further advantages are easy and comfortable applicability if atreatment is carried out with a device according to the invention.

The specific biological, physical and chemical effects caused in aliving body by vibration therapy are still being investigated in futuretrials, but the general effects are discussed in the following. Thegeneral effects of vibration therapy comprise vasodilatation,stimulation of cells, and enhancement of secretion clearance (forexample by promoting transport and/or (out)flow) among others.

In the following, it is shown on the example of the treatment of chronicrhinosinusitis (CRS) how these effects cause a significant therapeuticeffect. The vibration generator and device are in particular configuredto cause at least one of these effects and hence to cause saidtherapeutic effect (as shown in the “application example” given below).

If a device for vibration therapy is applied on the cheekbone for thetreatment of CRS (chronic rhinosinusitis), vibrations propagate to theparanasal sinuses like the maxillary sinus and to the nasal cavity andset the paranasal sinuses and the nasal cavity in oscillation. Theseoscillations accelerate the transport in the nose of excessive mucus andsecretions, for example by mechanically induced transport and/or byincrease of the mucociliary clearance, and stimulate the nasal andparanasal epithelium, for example by setting the epithelium in vibrationand by vasodilatation. Both accelerated transport and stimulationaccelerate the healing process, in particular reduce inflammation, andcontribute to an opening of the ostium of the paranasal sinuses. Thelatter in combination with a vibrating maxillary sinus allows for apromptly release of nitric oxide (NO) from the paranasal sinuses intothe nasal cavity. In addition, the vibration of the maxillary sinuspresumably promotes NO production. There are indications that a high NOconcentration has a protective or even healing effect, said effect beingactive in the maxillary sinus and nasal cavity due to the givenmechanism of action.

In summary, vibration therapy enhances and accelerates the healingprocess, reduces the pathognomonic symptomatology of CRS (e.g. facialpain, congestion, rhinorrhoea, etc.) and improves the well-being of thepatient with CRS both in the short and long-term. In other words, itshows anti-inflammatory, antioedematous and antiallergic effects,promotes normalisation of body defences, and may be used as monotherapy.The method is physiological, and it reduces the number of punctures inmaxillary sinusitis, leaves the skin and mucosa intact, and decreasesthe use of drugs.

The mechanism of action summarized in the preceding paragraphs will befurther explored using the vibration generator and device disclosed.

The effect of applying a vibration generator and a device as disclosedwill be further explored in clinical tests. It is envisaged to evaluateat least one of the change in subjective symptoms as quantified by theGerman validated disease-specific 20-item Sino-nasal Outcome Test(SNOT-20 GAV), the change in endoscopic appearances, the change in needfor surgical intervention, the change in the ability to perform normalactivities, overall disease control, acceptability of treatment, overallscore SNOT-20, pain score (VAS), and adverse events.

Vibration therapy in general has the potential for treating variousmedical conditions and reasons for physical uneasiness based on thebiological, physical and chemical effects mentioned above and if theapplied vibrations have characteristics suitable to cause these effects.

There are indications that vibration therapy increases angiogenesis andgranulation tissue formation and reduces neutrophil accumulation andincreases macrophage accumulation. Additionally, it may increaseexpression of pro-healing growth factors and chemokines (insulin-likegrowth factor-1 (IGF-1), vascular endothelial growth factor (VEGF) andmonocyte chemotactic protein-1) in wounds (Eileen M. et al., 2014; PLoSONE 9(3)). Vibration exposure may increase gene expression ofcollagen-1a (3-fold), IL-6 (7-fold), COX-2 (5-fold), andbone-morphogenetic-protein-12 (4-fold) (Thompson W et al., TheOrthopaedic Journal of Sports Medicine, 3(5)).

It is an object of the invention to provide a linear vibration generatorthat overcomes drawbacks of state-of-the-art linear vibrationgenerators.

In particular, it is an object of the invention to provide a linearvibration generator and a device comprising such a vibration generatorthat overcome drawbacks of state-of-the-art linear vibration generatorsand devices with respect to medical applications, in particular withrespect to vibration therapy, such as modulated vibration therapy.

For example, it is an object of the invention to provide a linearvibration generator and a device suitable for the treatment of CRS by(external) vibration therapy, in particular modulated vibration therapy.

For example, it is an object of the invention to provide a linearvibration generator with improved frequency tuning properties. Inparticular, it is an object to provide a linear vibration generatorcomprising a mass that is configured to carry out an oscillatory motion,wherein the vibration generator is tunable over a frequency range ofinterest and wherein the amplitude of the oscillation is morehomogeneous over the whole frequency range of interest compared tostate-of-the-art linear vibration generators.

For example, it is an object of the invention to provide a linearvibration generator suitable for generating more powerful impulsescompared to state-of-the-art linear vibration generators.

At least one of these objects is achieved by the devices and methodsaccording to the claims.

In particular, the axle is firmly mounted to the housing. In otherwords, the axle does not move relative to the housing, but it is an axleof the oscillatory motion of the mass.

In particular, the axle is a straight axle.

The axle can define a (directional) axis that can be a longitudinalaxis.

The mass comprises the permanent magnet and the coil is fixed to thehousing.

The mass can have a weight of at most about 50 g, 40 g, 30 g, 25 g, 20g, or 15 g.

The mass can have weight of at least about, 1 g, 2 g, 5 g, or 10 g.

In embodiments, the mass is preferably between 2 g and 20 g.

The weight of the mass can depend on the application. In other words,the vibration generator can be adapted to an application by comprising amass that is optimized for this application.

An amplitude of the oscillatory motion can be at most about 50 mm, 45mm, 40 mm, 35 mm, 30 mm, 25 mm, 20 mm, 15 mm, 10 mm, 5 mm, or 2 mm. Theamplitude can depend on the application. In other words, the amplitudecan be adapted to an application. For example, the amplitude can bebelow 5 mm, in particular below 2 mm for treatments of the paranasalsinuses of a human being.

For example, the amplitude can be 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm.

The vibration generator may be configured for oscillations of at leastabout 1 Hz, 5 Hz, 10 Hz, 20 Hz, 30 Hz, 40 Hz, 50 Hz, 60 Hz, 70 Hz, 80Hz, 90 Hz, or 100 Hz.

The vibration generator may be configured for oscillations of at mostabout 2000 Hz, 1900 Hz, 1800 Hz, 1700 Hz, 1600 Hz, 1500 Hz, 1400 Hz, or1300 Hz.

The vibration generator can be configured for oscillations preferably inthe range of 1 Hz to 2000 Hz, more preferably in the range of 20 Hz to1500 Hz, and more preferably in the range of 60 Hz to 1300 Hz. In otherwords, the oscillations are preferably in the range of 1 Hz to 2000 Hz,more preferably in the range of 20 Hz to 1500 Hz, and more preferably inthe range of 60 Hz to 1300 Hz. Typically, the oscillations sweep in arange of at least about 60 Hz to at most about 1300 Hz.

It is an insight that the vibration generator disclosed is in particularsuitable to work in the range of 60 Hz to 1300 Hz because the amplitudeof an oscillatory motion of a vibration generator of the kind describedincreases with decreasing frequency. Further, the amplitude andfrequency of the oscillatory motion of a vibration generator of the kinddisclosed can be well controllable in said range. In particular,amplitude and frequency can be better controlled in comparison toalternative vibration generators.

One can envisage various shapes of the permanent magnet, such as ring-,disc-, or square shape.

The permanent magnet can comprise Neodymium, for example. In otherwords, it can be a so-called Neodymium magnet.

In an embodiment the permanent magnet is a ring magnet, wherein the ringmagnet and the coil are arranged concentrically around the axle. Forexample, the ring magnet and the coil can be arranged concentricallyaround the axle, wherein the coil is arranged closer to the axle thanthe ring magnet.

The ring magnet and the coil can be offset along the axle.

The vibration generator can comprise a plurality (i.e. two or more) ofring magnets. In this case, the ring magnet mentioned before can beconsidered as a first ring magnet.

The further ring magnet(s) can be arranged concentrically with respectto the axle, too.

The further ring magnet(s) can have the same dimensions as the firstring magnet, and it/they can be offset along the axle. For example, afurther ring magnet can be offset along the axle and can be adjacent tothe first ring magnet.

The number and arrangement of the further ring magnet(s) can be suchthat the magnetic field, in particular the magnetic field strengthand/or the magnetic field distribution, is optimized with respect to themass used and/or desired treatment.

In an embodiment, the mass comprises a slit and the slit isconcentrically with respect to the axle, too.

In this embodiment the coil can be arranged in the slit. This also meansthat the slit is or comprises an annular aperture (a ring-shapedopening) that is closer to the axle than the first and—as the case maybe—at least one further ring magnet.

In an embodiment, the mass and the ring magnet (or ring magnets) areconfigured to generate an essentially homogeneous magnetic field in asection of the slit, wherein the homogeneous field runs radial to theaxle in this section of the slit at least.

For example, the section of the slit in which the essentiallyhomogeneous field is generated can be formed by a portion of the massforming a core around which the ring magnet (or ring magnets) isarranged and a core ring. The portion of the mass comprising said coreis called “core bottom” in the following.

The core ring can be arranged with respect to the ring magnet(s) and thecore bottom in a manner that the essentially homogenous field isgenerated.

The core ring can comprise or can be of a material, in particular of ametal, that is well suited to conduct magnetic fields. In particular,the material can have a high saturation level, for example a saturationlevel that is greater than 1 T or greater than 1.5 T. The dimensions ofthe core bottom can be such that a saturation limit of the material(metal) in regard to magnetic field is not exceeded. Thus, the corebottom and core ring act in effect as guides for the magnetic fluxresulting in the essentially homogeneous magnetic field in the sectionof the slit.

In an embodiment, an extension of the coil in a direction parallel tothe axle, this means a length of the coil, is smaller than an extensionof the section comprising the homogeneous field, said extension of thesection being in a direction parallel to the axle, too.

In this embodiment, the vibration generator is configured such that thecoil is in the section comprising the homogeneous field independent ofthe orientation of the vibration generator.

In particular, it is in the section comprising the homogeneous field inan idle state of the vibration generator, this means in a state in whichno current flows in the coil.

The vibration generator can further be configured for the oscillatorymotion of the mass being restricted between two positions of maximumdeflection of the mass and for the coil being predominantly in thesection of homogeneous field.

In particular, the coil can be predominantly in the section ofhomogeneous field independent of the position of the mass between thetwo positions of maximum deflection.

A homogeneous magnetic field, in particular in combination with a coilas disclosed that oscillates in the homogenous field only orpredominantly is important to have a consistent and well controllableresponse of the movement of the mass to current generated in the coil.

In an embodiment, the extension of the coil in a direction parallel tothe axle is greater than the extension of the section in a directionparallel to the axle.

In this embodiment, the vibration generator is configured such that aportion of the coil extends over the full extension of the sectionindependent of the position of the mass.

Again, the oscillatory motion of the mass can be restricted between twopositions of maximum deflection of the mass.

An embodiment having the coil with an extension that is greater than therelated extension of the section has the advantage of a maximum numberof windings in the section and independent of the position of the mass,for example. This is advantageous in terms of actuation of the mass,such as actuation force.

In an embodiment, the vibration generator comprises at least one elasticelement that centers the mass when the vibration generator is notpowered.

In particular, the at least one elastic element centers the mass in amanner that the coil is arranged in the slit, in particular in thesection of the slit comprising the essentially homogeneous field.

In embodiments, the vibration generator comprises two elastic elements,for example two elastic elements arranged around or in proximity to thephysical axle.

In an embodiment, the at least one elastic element is compressed duringoscillation of the mass.

The elastic element or a plurality of elastic elements can be configuredto delimit the amplitude of the oscillation.

The elastic element(s) can be configured to delimit a maximal deflectionof the mass. In particular, the elastic element(s) can define the twopositions of maximum deflection.

Alternatively, the elastic element(s) can be configured such that a stopor a plurality of stops delimit the maximal deflection of the mass. Forexample, the stop can be given by a bearing of the elastic element(s),such as the housing and/or a coil bracket.

The elastic element can be a spring, in particular a coil spring.

For example, the vibration generator comprises two elastic elements,wherein one delimits the deflection (amplitude) of the mass in onedirection along the axle and the other one delimits the deflection ofthe mass along the other direction along the axle.

The mass can be suspended by the two elastic elements that may be a coilspring.

The vibration generator can be configured that no harmonics, inparticular no harmonics of significance with respect to the amplitude ofthe oscillatory motion of the mass at least, are in the frequency rangeused for the treatment. In other words, preferably the treatmentfrequency range is different to the resonance frequency of the deviceitself.

This can be done by coordinating the elastic properties of the elasticelement and the weight of the mass, for example.

In particular, the vibration generator can be configured that at leastthe first (basic) harmonic is outside, in particular below, thefrequency range used for treatment.

A vibration generator that is configured to have no harmonics or atleast no harmonics of significance with respect to the amplitude in adetermined frequency range is advantageous in combination withapplications comprising a sweep over a frequency range.

For example, the vibration generator or a device comprising thevibration generator can be configured to operate off-resonant. Thismeans that the vibration generator or device can be configured to omitor pass rapidly through frequencies or frequency ranges corresponding toharmonic frequencies.

In an embodiment, the coil is mounted on a support having good heattransfer properties, wherein the support is in thermal connection to ahousing of the vibration generator. The housing is of a material capableto absorb heat generated by the coil and transferred to the housing viathe support.

For example, the specific thermal capacity of the housing and/or thesupport can be larger than 400 J/kg⁻¹ K⁻¹. The housing and/or thesupport can comprise or consist of steel.

For example, the specific thermal capacity of the housing and/or thesupport can be greater than 900 J/kg⁻¹ K⁻¹. The housing and/or thesupport can comprise or consist of aluminium.

In an embodiment, the vibration generator or a device comprising thevibration generator can comprise a signal processing unit, wherein thesignal processing unit is configured to superimpose a control signal,this means the input signal used for generating the movement of themass, with a further signal.

The further signal and the vibration generator can be configured in amanner that an audio signal can be generated from the further signal.

The vibration generator can be configured to sweep over a plurality offrequencies. For example, the vibration generator (or a devicecomprising the vibration generator) can comprise a controller configuredto run the vibration generator in a manner comprising a sweep.

With respect to medical applications, there are indications that a sweepcan improve treatment efficiency by exciting a plurality of resonances,also resonances of different kinds as disclosed in relation to theapplication example below, for example.

The resonance frequencies can be subject-specific. The sweep can also beconfigured to make sure that at least one resonance frequency is in theapplied range of frequencies independent from the stimulated subject.

For example, the vibration generator or the device comprising vibrationgenerator can be configured to sweep over the frequency range of 60 to1300 Hz or a section of it.

The sweep over a plurality of frequencies can be characterised by asweep time, this means by the time needed for scanning from the lowestfrequency value of the plurality of frequencies to the largest frequencyvalue and back to the lowest value.

The sweep time can be at most about 60 s, 45 s, 30 s, 25 s, 20 s, 15 s,10 s, or 5 s. The sweep time can be at least about 0.5 s, 1 s, 1.5 s, 2s, 3 s, 4 s, or 5 s.

The sweep time is preferably between 0.5 s and 30 s, more preferablybetween 1 s and 10 s.

The plurality of frequencies can be given by any frequency rangedisclosed above.

The sweep time can vary during operation of the vibration generator. Inother words, a sweep rate can vary. In particular, the sweep time canvary during operation within any time range that arise from the sweeptimes disclosed above. For example the sweep time can vary between 0.5 sand 30 s or between 1 s and 10 s.

For example, the sweep time can decrease during operation. In otherwords, the sweep rate can increase. A decreasing sweep time (increasingsweep rate) can have the benefit of an increasing energy transfer fromthe vibration generator to a subject in contact with the vibrationgenerator.

The vibration generator or the device comprising the vibration generatorcan be configured to carry out a plurality of sweeps during operation.

The invention relates further to a device for applying oscillations(vibrations) to a subject to be stimulated, wherein the device comprisesa vibration generator in any embodiment disclosed.

It has been found that a vibration generator as disclosed comprisesvarious benefits that make the vibration generator suitable for beingused in oscillation (vibration) therapy:

-   -   The vibration generator comprising a coil, in particular a coil        as disclosed (and sometimes called a voice coil), can have        properties that make such a vibration generator very suitable        for use in the field of oscillation (vibration) therapy in        comparison to a piezoelectric transducer or a transducer        comprising a rotation mass, for example.        -   For example, such a vibration generator can generate            vibrations that are directed or even focused in a direction.    -   The vibration generator can be designed to have an amplitude of        the vibrations that is more homogeneous over the whole frequency        range of interest in the field of oscillation (vibration)        therapy compared to piezoelectric transducers or a transducer        comprising a rotation mass, for example. This is one reason why        the vibration generator can be well suited for the frequencies        at the upper end of the frequency range of interest.        -   In particular, a design in which the mass comprises the            magnets leads to a heavier mass and allows for higher            intensities without increasing space requirements and            without increasing the overall weight of the vibration            generator. It further allows for a more homogeneous magnetic            field in the actuation region of the vibration generator            without increasing space requirements and without increasing            the weight of the vibration generator. A more homogeneous            magnetic field in the actuation region leads to a more            linear response of the vibration generator to the electric            input signal and to a more homogeneous amplitude over the            frequency range of interest, for example.

In particular, the device can be configured for the treatment ofparanasal sinuses, for example for the treatment of chronic rhinosinusitis.

In an embodiment, the device comprises a device head and optionally adevice body, wherein the vibration generator is arranged in the devicehead.

The device body can be designed for being held by a user.

The device can be a handheld device.

The device can be portable.

The device can be configured for a drug free use.

The device can be configured for a non-invasive use.

The device, in particular the device head, can be designed to comprise asurface (called “contact surface” in the following) that can be broughtin contact to the subject, for example when the device is held at thedevice body and when the device is in a state suitable for stimulationof the subject.

The device can be configured for direct contact between the surface andthe subject, this means between the surface and the skin of the bodyportion to which the device is applied, during use. In other words,there is no need for an intermediate element or layer between thesurface and the skin. In particular, there is no need for a gel and thelike.

In an embodiment, the device head is movable to a first positionrelative to the device body and to a second position relative to thedevice body.

The device comprises further a controller configured to switch thedevice in a sleeping mode if the device head is moved to the firstposition and to switch the device in an active mode, if the device headis moved to the second position.

In an embodiment, the device head is in addition movable to a thirdposition relative to the device body, wherein the third position allowsaccess to the contact surface for cleaning.

In this embodiment, the controller is configured further to switch thedevice in the sleeping mode if the device head is moved to the thirdposition.

For example, the device body can comprise a recess and the device headcan be designed in a manner that it can be stored completely in therecess. In particular, the device head can be flush with the devicebody.

In this case, the position of the device head in which it is storedcompletely in the recess can be the first position.

In this case, the first position can also be considered as a closedposition.

A device head being in the closed position is prevented from at leastone of contamination, unintentional start and damage, for example.

The device can be equipped for the device head being moved out at leastpartly of the recess.

For example, the device can comprise an axis around which the devicehead can be pivoted or along which the device head can moved.

If the device comprises the axis around which the device head can bepivoted and if a rotation angle of 0° corresponds to the first position(closed position, device in sleeping mode), the second position (activemode) can be at a rotation angle between 90° and 150° degrees, forexample. For example, the second position can be between 110° and 130°,such as at 115°, 118°, 120°, 122° or 125°.

In particular, the second position can be at most about 150°, 145°,140°, 135°, or 130°. The second position can be at least about 90°, 95°,100°, 105°, or 110°.

In such configurations, the optional third position (cleaning mode) canbe at a rotation angle between 150° and 200° degrees, for example. Forexample, the third position can be at 160°, 170°, 180°, or 190°.

In an embodiment, the third position is at 180°.

The device can comprise fixation means that allow automatic or manualfixation of the device head relative to the device body in at least oneposition.

The device can be configured to move the device head to at least one ofthe first, second or third position in an automated manner.

Alternatively or in addition, the device can be configured to move thedevice head between at least two of the first, second and third positionin an automated manner.

The device can comprise a motor, in particular an electric drive,configured to move the device head in an automated manner.

Alternatively or in addition to an automated movement of the devicehead, the device can be configured to move the device head manually.

In the sleeping mode and—if present—the cleaning mode, the vibrationgenerator can be inactive.

The device can be configured to start a stimulation in an automatedmanner, in particular to activate the vibration generator, in case thedevice head is moved to the second position.

The invention relates further to a method for treating a subject withoscillations. The method comprises a step of bringing a devicecomprising a vibration generator in any embodiment disclosed or a devicefor applying oscillations in any embodiment disclosed in contact withthe subject.

The method can comprise a step of treating the subject during atreatment time of at least about 0.5 s, 1 s, 2 s, 5 s, 10 s, 15 s, or 20s.

The method can comprise a step of treating the subject during atreatment time of at most about 5 min, 4 min, 3 min, 2 min, 90 s, 60 s,45 s, or 30 s.

The treatment time can be between 0.5 s and 2 min, for example between 2s and 90 s, 2 s and 60 s, or 5 s and 30 s. For example, it can be 5 s,10 s, 15 s, 20 s, 25 s, 30 s, 45 s, 60 s, 75 s, 90 s, 105 s, or 120 s.

The method can comprise a step of carry out the treatment a plurality oftimes. In other words, the method can comprise a plurality of treatmentsessions.

The subject matter of the invention will be explained in more detail inthe following text with reference to exemplary embodiments which areillustrated in the attached drawings, which schematically show:

FIG. 1 shows an exterior view of an exemplary embodiment of a device 1for applying oscillations (vibrations) to a subject by comprising avibration generator 10.

The device 1 shown is a compact, handheld device.

The device comprises a device body 2 and a device head 3, wherein thedevice head 3 hosts the vibration generator 10.

The device head 3 shown comprises a contact surface 4 that is arrangedto be brought at least partly in contact with the subject to be treated.

The contact surface 4 may be a surface of an interchangeable part 5 ofthe device 1

In the embodiment shown, the contact surface 4 comprises an indentation7 in the shape of a convex recess.

The device head 3 shown is pivoted with respect to the device body 2(indicated by a double arrow). The pivotal mounting can be such that thedevice head 3 can be brought at least in the first and second positionsrelative to the device body 2 mentioned above. In addition, the devicehead 3 can be optionally brought at least in the third positionmentioned above.

In other words, the device head 3 shown is a movable device head.

The device shown comprises further user interface 26 comprising aplurality of LEDs. The LEDs can indicate at least one of a status of thedevice and a status (advancement) of a treatment or a session oftreatments.

FIG. 2 shows an external view of a further exemplary embodiment of adevice 1 comprising the vibration generator 10.

The device 1 shown may be handheld, however it is not as compact as thedevice 1 of FIG. 1. In other words, the device 1 of FIG. 2 is rathersuitable for being installed in or provided by hospitals andprofessionals whereas the device 1 of FIG. 1 is rather suitable for useby a wider public and can be carried around by a user, for example.

The device 1 of FIG. 2 comprises—in comparison with the device 1 of FIG.1 at least—a powerful computerized device 29 and a more detailed userinterface 26. Optionally, it can comprise a fixture or grip 28.

FIG. 3 shows mainly an external view of an exemplary embodiment of adevice head 3 comprising the vibration generator 10.

The device head 3 shown is a handheld device head 3, wherein the devicebody 2 can be handheld, for example a cell phone or a tablet, or firmlyinstalled, such as a personal computer (PC) or another computerizeddevice, e.g. as shown in FIG. 2.

The device body 2 can supply the device head 3 with power and/or controlsignals, for example. In the embodiment of FIG. 3, such supply iscarried out by a wired connection between device head 3 and device body2.

FIG. 4 shows an exploded view of the device 1 shown in FIG. 1.

In the embodiment shown, a housing of the device body comprises a frontpart 41 and a rear part 42.

The rear part 42 is equipped to hold a battery 8, for example arechargeable battery.

Front and rear part are designed to host the more sensitive parts of thedevice 1, such as a Printed Circuit Board (PCB) 22, a controller 23.1 ofthe device 1, components of the user interface 26, such as LEDs 9 and atleast one manual control element 43 (control knob, button etc.), and atleast one support 44 for the device head 3, which is a movable devicehead in the embodiment shown.

FIG. 5 shows an exploded view of an exemplary embodiment of the devicehead 3 shown in FIG. 1.

The shape of the device head 3 is given by a housing 6 and theinterchangeable part 5.

The interchangeable part 5 can be mounted to the housing 6 by comprisinga protrusion arranged on the interchangeable part 5 to reach into thehousing 6 and designed to form a positive-fit connection with thehousing 6, for example.

The device head 3 shown comprises further a capacitive (touch) sensor51, a transducer (vibration generator) 10, and a Printed Circuit Board(PCB) 22.

In the embodiment shown, the interchangeable part 5 comprising thecontact surface 4 and the indentation 7, the capacitive sensor 51 andthe PCB 22 are the main components of a sensor element 50 configured todetect a contact between the contact surface 4 and the subject and togenerate a related output signal.

The output signal is pressure dependent in some embodiments.

The PCB 22 comprises a controller 23.2 of the sensor element configuredto generate the output signal.

The PCB 22 can further comprise a memory 24 and/or communication means25 to a computerized device 29.

In an alternative embodiment, the capacitive sensor 51 comprises thecontroller 23.2, the memory 24 and/or the communication means 25.

The communication means 25 can be wireless communication means or wiredcommunication means, as it is the case in the embodiments of FIGS. 2 and3, for example.

The computerized device 29 can be a handheld (portable, mobile)computerized device, such as a cell phone or a tab, or it can be afirmly installed computerized device as disclosed with respect to FIGS.2 and 3.

The computerized device 29 can comprise a user interface 26 and can beconfigured to run an application (program) suitable for at least one ofcontrolling the device 1, comparing a characteristic of the outputsignal with a present value, determining whether the characteristic ofthe output signal is greater than a pre-set value, generating an enablesignal, setting a timestamp when a treatment is started, determining atreatment regularity, determining a treatment completeness, determininga contact quality, determining a treatment quality, selecting a desiredtreatment, and indicating the target position and optionally the targetorientation, for example.

The treatment regularity expresses whether a sequence of treatments iscarried out with a regularity needed for a given application. Forexample, the treatment regularity can be determined by comparing aperiod between two timestamps with a pre-set period, wherein the pre-setperiod can be an optimal period between two treatments for a specifictreatment.

The treatment completeness expresses whether the number of treatmentscarried out is sufficient for a given application. For example, thetreatment completeness can be determined by comparing a number oftimestamps set during a period (e.g. a day or a week) in which theoverall treatment is planned to take place time with a pre-set number oftreatments.

The contact quality expresses whether the contact between the device 1and the subject to be stimulated is sufficient during a treatment for agiven application. For example, the contact quality can be determined bydetermining whether the characteristic of the output signal is greaterthan a pre-set value repeatedly during a treatment and by setting thenumber of characteristics greater than the pre-set value in relation tothe total number of output signals analyzed.

The treatment quality expresses whether a treatment is carried out onthe subject under conditions that result in a good treatment. Forexample, the determination of the treatment quality can comprise readingout the pressure dependent output signal, in particular the value of thecharacteristic that is related to the contact pressure, repeatedlyduring a treatment and setting the read-out pressure dependent outputsignals in relation to a target value. The target value may be atime-dependent target value.

For example, the determination of the treatment quality can comprisedetermining a ratio between an integral of the time evolution of theread-out pressure dependent output signal and an integral of the timeevolution of a target pressure. In this case, a ratio lager than 1 canbe considered as a good contact quality leading to a good treatmentquality, for example.

For example, the determination of the treatment quality can comprisedetermination of a percentage. For example, a good treatment quality canbe assumed if the read-out pressure dependent output signal is greaterthan the target value during at least 50% of the treatment time, inparticular during at least 60%, at least 70%, at least 80% or at least90% of the treatment time. In other words, a good treatment quality isensured if the pressure applied during the treatment time is above apressure threshold value during at least 50%, at least 60%, at least70%, at least 80% or at least 90% of the treatment time.

The controller 23.2 in combination with the memory 24 and/or userinterface 26 as the case may be can be configured to carry out one, aplurality or all of the actions listed above. One, a plurality or all ofthe actions listed above can be carried out by the controller 23.1 ofthe device 1.

The controller 23.2 of the sensor element can be integrated in thecontroller 23.1 of the device 1. The memory 24 and/or the communicationmeans 25 can be arranged on a device PCB 22 as shown in FIG. 4, forexample.

FIG. 6 shows an exploded view of a further exemplary embodiment of adevice head 3.

In the embodiment shown, the contact surface 4 comprising theindentation 7 is an integral part of the housing 6 of the device head 3.

Due to this, the design of some components of the device head 3 isdifferent compared to the device head 3 according to FIG. 5. Forexample, the device head 3 comprises a cover plate 39 for closing thedevice head 3 after arranging the sensor element 50 and the vibrationgenerator 10 in the housing 6.

The exploded view of FIG. 6 shows further bearing (37, 38) for a pivotalmounting of the device head 2 and ducts 44 for wires. A duct in thecover plate 39, a duct in a bearing 37, and a duct on the vibrationgenerator 10 is visible in the exemplary embodiment of FIG. 6.

The exploded view of FIG. 6 shows further buffers 40, for example rubberbuffers.

FIG. 7 shows a sectional view of the (assembled) device head 3 of FIG.5. Among other things, details of the vibration generator 10 and thepositive-fit connection between the interchangeable part 5 and thehousing 6 are shown.

Details of an exemplary embodiment of the vibration generator 10 aredisclosed with respect to FIGS. 8 to 11:

FIG. 7 shows a gasket 52 for sealing an interior of the device head 3 inaddition to the components shown in FIGS. 5 and 8-11.

FIG. 8 shows an exploded view of an exemplary embodiment of a vibrationgenerator 10.

The shape of the vibration generator is given by a housing 14 of thevibration generator and a so-called coil bracket 30.

The vibration generator 10 comprises further a (physical) axle 31defining a (directional) axis 15, a permanent magnet (two ring magnets13 in the embodiment shown), a so-called core ring 34, a so-called corebottom 35, and a coil 12 (not shown in FIG. 11), in particular a coil asdisclosed in the following. A coil as disclosed in the following issometimes called a voice coil 12.

The coil bracket 30 can be considered as a base of the vibrationgenerator 10, said base comprising a support 21 for the coil 12.

The mass 11, this means the component of the vibration generator 10 thatcan be actuated to carry out an oscillatory motion along the axis 15,comprises the core bottom 35, the permanent magnet (the ring magnets 13in the embodiment shown) and the core ring 34.

The core bottom 35 can account for most of the weight of the mass 11.The weight of the core bottom 35 can be adjusted to the application.

The vibration generator 10 comprises further two elastic elements (coilsprings 20) in the embodiment shown. The springs 20 are configured tocenter the mass and to generate a repelling force to the mass 11.

In the embodiment shown, it is the housing 14 and the coil bracket 30that delimit the maximum deflections of the mass 11 by the elasticelements (coil springs 20) being partly arranged in a recess of the corebottom and the coil bracket 30, respectively.

FIG. 9 shows a sectional view of the assembled vibration generator ofFIG. 8.

In the embodiment shown, one end of the axle 31 is mounted to the coilbracket 30 and the other end of the axle 31 is mounted to the housing14.

A first spring 20 is arranged around the axle 31 at its mounting pointto the housing 14 and a second spring 20 is arranged around the axle 31at its mounting point to the coil bracket 30.

The housing 14 and first spring 20 as well as the coil bracket 30 andthe second spring 20 define maximal deflections of the mass.

The coil bracket 30 is mounted to the housing 14, for example by screws33.

In the embodiment shown, the core bottom 35, the ring magnets 13 and thecore ring 34 are arranged concentrically with respect to axis 15.

Further, the core bottom 35, the ring magnets 13 and the core ring 34are firmly mounted to each other, for example by gluing. In other words,the mass 11 is formed integrally (one-piece).

The core bottom 35 comprises a protrusion 36, wherein the ring magnets13 and the core ring 34 are arranged around the protrusion 36.

The protrusion 36 is designed for forming a slit 16 between theprotrusion 36 and the core ring 34. The slit 16 runs concentrically withrespect to the axis 15.

The protrusion 36 can be designed further for the slit 16 being formedbetween the ring magnets 13 and the protrusion 36, too.

The core ring 34 and a portion of the protrusion 36 that forms the slit16 between the core ring 34 and the protrusion 36 can be designed for anoptimized magnetic field in a section 17 of the slit 16 formed by thecore ring 34 and the protrusion 36.

The magnetic field is optimized in terms of homogeneity, for example.

In the embodiment shown, the magnetic field lines run (or rather have torun) radial to the axis 15 in said section 17 of the slit 16.

The support 21 and the coil 12 held in position by the support 21 aredesigned for extending into the slit 16 in a manner that at least aportion of the coil 12 is arranged in the section 17 of the slit 16formed by the core ring 34 and the protrusion 36. In particular in theidle state of the vibration generator 10, at least a portion of the coil12 is in said section 17.

FIG. 10 shows a detail view of the coil 12, the coil ring 34 and theprotrusion 36 in the section 17 of optimized magnetic field, this meansin an actuation region of the vibration generator 10.

In the embodiment shown, an extension 18 of the section 17, saidextension 18 being parallel to the axis 15, is smaller than a relatedextension 19 of the coil 12.

In particular, the extension 19 of the coil 12 is such that a portion ofthe coil 12 extends over the full extension 18 of the section 17independent of the position of the mass 11.

As shown with respect to FIG. 9, the position of the mass 11 is withintwo positions of maximal deflection.

A configuration between the coil 12 and the section 17 as shown in FIG.10 has the advantage of a maximum number of windings being always withinthe actuation region. This is advantageous in terms of actuation of themass, such as actuation force.

FIG. 11 shows a detail view of an alternative actuation region.

In the embodiment shown, the extension 18 of the section 17 is largerthan the related extension 19 of the coil 12.

In particular, the extension 19 of the coil 12 is such that the wholecoil 12 is within the section 17 of optimized magnetic field at least inidle state but independent of the orientation of the vibration generator10.

Optionally, the whole coil 12 is within the section 17 of optimizedmagnetic field independent of the position of the mass 11.

A configuration between the coil 12 and the section 17 as shown in FIG.11 has the advantage of the coil 12 being in region of homogeneousmagnetic field only. This is advantageous in terms of response behaviourof the mass 11 and controllability of the oscillatory motion of themass, for example.

FIGS. 12-15 show an application example of the vibration generator andthe device, namely the treatment of chronic rhinosinusitis (CRS) bymodulated vibration therapy and by use of a device 1 as shownexemplarily in FIGS. 1 and 4 and comprising a vibration generator 10 asshown exemplarily in FIGS. 8-10.

FIG. 12 shows a model of a human skull. The human skull (more preciselythe human head) is the subject 100 in the application example. Such amodel of the human skull was used to carry out numerical simulation withthe aim to get information about the mechanical, in particularvibrational, properties of the human head and to supply indications ofthe vibrational excitation of the maxillary sinuses (left maxillarysinus 102.1, right maxillary sinus 102.2) and of the frontal sinuses103.

The sinuses cannot be seen in FIG. 12 because they are arranged insidethe skull (mainly behind maxilla and frontal bone, respectively).

FIG. 13 visualizes a numerically calculated deformation of the leftmaxillary sinus 102.1 when excited by vibrational energy with afrequency close to a numerically calculated resonant frequency of themaxillary sinus and when the vibrational energy is coupled into theskull by a vibration generator at the application point 101, this meansby a vibration generator in contact with the zygomatic bone 104 at theindicated application point 101.

The colours are indicative for the degree of deformation, wherein thecolour next to H indicates a high deformation and the colour next to Lindicates a low deformation.

FIG. 14 visualizes a numerically calculated deformation of the rightmaxillary sinus 102.2 when excited as discussed in relation to FIG. 13.This means, an effect on the right maxillary sinus 102.2 when thevibrational energy is coupled into the left zygomatic bone 104 is shown.

Again, the colours are indicative for the degree of deformation, whereinthe colour next to H indicates a high deformation and the colour next toL indicates a low deformation.

FIGS. 13 and 14 show snapshots of the deformation of the maxillarysinuses due to the vibrational energy coupled into the left zygomaticbone 104, only. The time-dependent deformation of the maxillary sinusesis an oscillating deformation between the deformation states shown inFIGS. 13 and 14 and an opposite state.

FIGS. 13 and 14 suggest that the maxillary sinuses can be excited tooscillating deformation by vibrational energy of a specific frequency,i.e. a resonant frequency of the maxillary sinuses, applied to thezygomatic bone 104.

FIGS. 13 and 14 suggest further that a coupling of vibrational energyinto the left zygomatic bone may not only have an effect on the leftmaxillary sinus 102.1 but also on the right maxillary sinus 102.2, andvice versa.

The frequency of the vibrational excitation resulting in FIGS. 13 and 14was around 355 Hz. However, the numerical simulations suggest variousfurther resonance frequencies between 100 Hz and 1300 Hz, at least.

The numerical simulations carried out supply indications of thestructure-mechanical properties of a sinus. Another aspect of thevibrational properties of a sinus can be obtained by approximating thesinus by a Helmholtz resonator and by using the Helmholtz equation toestimate air resonances in the cavity formed by the sinus (by theHelmholtz resonator). A basic resonance frequency of around 27.6 Hz forthe sinuses shown in FIGS. 13 and 14 can be calculated from theHelmholtz equation.

Hence, the numerical simulations and the Helmholtz equation suggest thatthere are resonances of both structure-mechanical and geometrical kindin a frequency range between 20 Hz and 1300 Hz at least, wherein thestructure-mechanical resonances can be excited by the device 1 appliedto the zygomatic bone 104. Further, it is conceivable that thevibrations applied to the zygomatic bone 104 can excite the resonancesof geometrical kind (i.e. the Helmholtz resonances) via deformation ofthe sinus if the sinus can be approximated by a Helmholtz resonator.

In principle, it is conceivable that an excitation ofstructure-mechanical and geometric resonances have a synergetic effect,for example by the structure-mechanical resonance(s) opening the ostiumof the sinus and enable the appearance of geometric resonance(s).

However, excitation frequencies below 60 Hz are preferably avoided dueto possible adverse effects.

Further, literature suggests resonant frequencies of the frontal sinusesbetween 160 Hz and 1240 Hz.

In summary, a frequency range between 60 Hz and 1300 Hz is a preferredfrequency range for the treatment of CRS.

Scanning over a frequency range, for example over the preferredfrequency range, guarantees that the sinuses are excited at variousresonant frequencies and it guarantees further that subject dependentvariations of the resonant frequencies of the sinuses do not have anadverse effect on treatment success.

The influence of sweep time, this means the time for scanning from thelowest frequency value of the preferred frequency range to the largestfrequency value and back to the lowest value, on energy transmissionfrom the device 1 to the subject 100 was estimated experimentally. Theexperiments indicate an increased energy transmission for small sweeptimes, in particular for sweep times below 5 seconds, whereas the energytransmission is essentially constant for sweep times between 5 and 30seconds, at least.

In other words, low sweep times seem to be preferable in terms ofefficient energy transmission from the device 1 to the subject 100.However, low sweep times are often found unpleasant by the user(patient). Further, the influence of sweep time on the excitationefficiency of the sinuses has to be studied further yet.

Hence, a sweep time that changes during a single treatment seems to beadvantageous. Further, a changing sweep time can be used to make theusers perception of the treatment less boring and/or to signal theapproaching end of the treatment to the user.

FIG. 15 shows an exemplary course of the vibration frequency produced bythe device 1 for CRS treatment. The sweep time decreases from 10 s to1.5 s. The scanned frequency range is 60 Hz to 1300 Hz.

One can envisage other course of the vibration frequency, for example acourse with a constant sweep time and/or sweep time(s) that are within arange given by efficient resonant excitation of a sinus.

A method for treating chronic rhinosinusitis (CRS) by modulatedvibration therapy can be as follows when considering the above:

-   -   The contact surface 4 of the device 1 is applied to the        application point 101 on skin over the left cheekbone of the        subject 100.    -   The device 1 is activated, this means the device generates        vibrations in the frequency range between 50 Hz and 1600 Hz, in        particular between 60 Hz and 1300 Hz, wherein the frequency        range is repeatedly scanned with a sweep time between 0.5 s and        30 s, for example between 1 s and 10 s.        -   The sweep time can vary during the treatment. For example,            the course of the vibration frequency can be as shown in            FIG. 15.    -   The device 1 is deactivated after a pre-set treatment time. The        treatment time can be in the range of 0.5 s to 2 minutes, for        example 1 minute, in the case of CRS treatment.    -   The treatment is repeated on the right cheekbone.        -   The treatment time can be longer than the above-disclosed            0.5 s to 2 minutes if the treatment is carried out at one            cheekbone, only. In this case, the treatment time can be 2            or 3 minutes or between 2 and 3 minutes, for example.

The method for treating CRS usually comprises a plurality of treatmentsessions. This means, the steps listed above are repeated a plurality oftimes in a given period. In particular, 3 to 4 treatment sessions arecarried out per day.

1. A vibration generator comprising a mass, a coil, a permanent magnetand a housing, wherein the mass can be set in an oscillatory motion withrespect to the housing by applying a current to the coil, and thevibration generator further comprising an axle, wherein the oscillatorymotion is along the axle, and in that the mass comprises the permanentmagnet and the coil is fixed to the housing.
 2. The vibration generatorof claim 1, wherein the permanent magnet is a ring magnet, wherein thering magnet and the coil are arranged concentrically around the axle. 3.The vibration generator of claim 1, wherein the mass comprises a slit,wherein the slit is arranged concentrically with respect to the axle andwherein the coil is arranged in the slit.
 4. The vibration generator ofclaim 3, wherein the mass and the permanent magnet are configured togenerate an essentially homogeneous field in a section of the slit,wherein the homogeneous field runs radial to the axle in this section ofthe slit.
 5. The vibration generator (10) of claim 4, wherein thesection is formed between a core ring and a core bottom, wherein thecore ring is of a material having a high saturation level and whereinthe core bottom is configured to not exceed a saturation limit of thematerial having the high saturation level.
 6. The vibration generator ofclaim 4, wherein an extension of the coil in a direction parallel to theaxle is smaller than an extension of the section in a direction parallelto the axle and wherein the vibration generator is configured such thatthe coil is in the section independent of the orientation of thevibration generator.
 7. The vibration generator of claim 5, wherein thevibration generator is configured for the oscillatory motion beingrestricted between two positions of maximum deflection of the mass andwherein the vibration generator is configured for the coil beingpredominantly in the section of the homogeneous field.
 8. The vibrationgenerator of claim 4, wherein an extension of the coil in a directionparallel to the axle is larger than an extension of the section in adirection parallel to the axle, wherein the vibration generator isconfigured for the oscillatory motion being restricted between twopositions of maximum deflection of the mass and wherein the vibrationgenerator is configured for a portion of the coil extending over thefull extension of the section independent of the position of the mass.9. The vibration generator of claim 1, wherein the vibration generatorcomprises an elastic element that centers the mass when the vibrationgenerator is not powered.
 10. The vibration generator of claim 9,wherein the elastic element is compressed during operation of thevibration generator.
 11. The vibration generator of claim 1, wherein thevibration generator is configured to have its basic harmonic outside thefrequency range in which the vibration generator is operated.
 12. Thevibration generator of claim 11, wherein the vibration generator isconfigured to have no harmonics of significance with respect to theamplitude of an oscillatory motion of the mass in the frequency range inwhich the vibration generator is operated.
 13. The vibration generatorof claim 1, wherein the coil is mounted on a support having good heattransfer properties, wherein the support is in thermal connection to thehousing, and wherein the housing is of a material capable to absorb heatgenerated by the coil and transferred to the housing via the support.14. The vibration generator of claim 1, comprising a signal processingunit, wherein the signal processing unit is configured to superimpose acontrol signal used for the oscillatory motion of the mass with afurther signal, wherein the further signal and the vibration generatorare configured in a manner that an audible signal can be generated fromthe further signal by the vibration generator.
 15. The vibrationgenerator of claim 1, wherein the vibration generator is configured tosweep over a plurality of frequencies.
 16. The vibration generator ofclaim 1, wherein the vibration generator is configured to oscillate at afrequency of not less than 1 Hz, 5 Hz, 10 Hz, 20 Hz, 30 Hz, 40 Hz, 50Hz, 60 Hz, 70 Hz, 80 Hz, 90 Hz, or 100 Hz.
 17. The vibration generatorof claim 1, wherein the vibration generator is configured to oscillateat a frequency of not more than about 2000 Hz, 1900 Hz, 1800 Hz, 1700Hz, 1600 Hz, 1500 Hz, 1400 Hz, or 1300 Hz.
 18. The vibration generatorof claim 1, wherein the vibration generator is configured foroscillations in the range of 1 Hz to 2000 Hz, more suitably in the rangeof 20 Hz to 1500 Hz, and optionally in the range of about 60 Hz to about1300 Hz.
 19. The vibration generator of claim 1, wherein the vibrationgenerator is configured to sweep over a frequency range of about 60 toabout 1300 Hz, or a section thereof.
 20. The vibration generator ofclaim 19, wherein the sweep occurs over a time period of at most about60 s, 45 s, 30 s, 25 s, 20 s, 15 s, 10 s, or 5 s.
 21. A device forapplying oscillations to a subject to be stimulated, comprising avibration generator according to claim
 1. 22. The device of claim 21,comprising a device head and a device body, wherein the vibrationgenerator is arranged in the device head.
 23. The device of claim 22,wherein the device head is movable to a first position relative to thedevice body and to a second position relative to the device body,wherein the device comprises a controller configured to switch thedevice in a sleeping mode if the device head is moved to the firstposition and to switch the device in an active mode, if the device headis moved to the second position.
 24. The device of claim 23, wherein thedevice head is movable to a third position relative to the device body,wherein the third position allows access to a contact surface forcleaning and wherein the controller is configured to switch the devicein the sleeping mode if the device head is moved to the third position.25. A method for treating a subject with oscillations, characterized bycomprising a step of bringing a device comprising the vibrationgenerator according to claim 1 in contact with the subject.